Cross-cultural adaptation and measurement properties of the Patient-Rated Tennis Elbow Evaluation for the Persian language

Abstract

Introduction

The Patient-Rated Tennis Elbow Evaluation (PRTEE) questionnaire is a tool designed for self-assessment of forearm pain and disability in patients with tennis elbow. The aims of this study were to translate and cross-culturally adapt the PRTEE questionnaire into Persian and evaluate its reliability and construct validity.

Methods

The PRTEE questionnaire was translated into and cross-culturally adapted to Persian in 90 consecutive patients with tennis elbow, according to well-established guidelines. Reliability was tested by means of test–retest and internal consistency. The measurement error was measured by calculating the standard error of measurement. Based on the standard error of measurement, the minimum detectable change was calculated. To evaluate construct and convergent validity, correlation with the PRTEE with the Disabilities of the Arm, Shoulder and Hand questionnaire and Visual analogue scale was used.

Results

In the process of cross-cultural adaptation, two items (6 and 8) were modified. In item 6, the term “door knob” was changed to “turn a key”, and in the item 8, “cup of coffee” was changed to “cup of milk”. Item-total correlations were greater than 0.55 (ranged from 0.55 to 0.76), internal consistency was high (Cronbach’s alpha, 0.94) and a high intraclass correlation coefficient (0.98) indicated excellent reliability of the P-PRTEE. The standard error of measurement and minimum detectable change were 5.40 and 14.24, respectively. The Persian version of the PRTEE questionnaire (P-PRTEE) shows strong construct and convergent validity (r values = 0.85, p < 0.05).

Conclusions

The P-PRTEE is valid and reliable in assessing disability and pain in Persian patients with tennis elbow. The excellent psychometric properties of the P-PRTEE endorse the use of this questionnaire in clinical settings.

Keywords

Tennis elbow lateral epicondylitis reliability validity psychometric properties cross-cultural adaptation

Introduction

Tennis elbow (TE), also known as lateral epicondylitis is a common musculoskeletal condition associated with pain at the elbow joint due to the degeneration of extensor carpi radialis brevis origin or the other extensor tendons of forearm.¹ Work-related or sport-related pain is the most common complaint of the patients with TE.² Pain is caused by overuse, repetitive resisted wrist extension, muscle imbalance, training errors, and psychological factors. This results in loss of function, limitations, and disability.³

Detection of pain and limitations in function can help to evaluate the effectiveness of treatments and changes of symptoms over time. For decades, the measurement of outcomes in elbow pathologies has relied on general patient-reported outcome measures. Mostly the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH) has been used to measure function and symptoms in patients with upper extremity conditions. The DASH consists of 30 items and is confirmed to have acceptable measurement properties to evaluate function and disability.⁴ It has been used in patients with TE.^5,6 However, it is thought that disease-specific questionnaires can better diagnose, screen, and determine the outcomes. Several assessment tools and questionnaires have been developed for elbow conditions.^4,7,8

The Patient-rated Elbow Evaluation (PREE) is one such questionnaire which is designed to measure pain and disability in patients with elbow injuries.⁹ In 2005, the PREE was modified to the Patient-Rated Tennis Elbow Evaluation questionnaire (PRTEE) as a disease-specific, patient-reported questionnaire.^6,10

The PRTEE has been specifically designed to measure pain and function in patients with TE over time. It provides a very quick and easy way to evaluate pain and function in patients with TE. Good psychometric properties of the PRTEE are reported in different languages.^11–20 The PRTEE is a 15-item questionnaire with two subscales addressing both pain and function (5 pain items, and 10 function items). Items are scored on a 0 to 10 scale, where 0 is the best possible score in each subscale. It takes an average of 6 min to complete the PRTEE. The total score is calculated as the sum of the pain items, plus half sum of the function items. The maximum score is 50 in each subscale and 100 in total, with higher scores indicating severe pain and limitations.¹⁰

There is no Persian version of the PRTEE available now for the general Persian population, except for a study, which reported psychometric properties of the Persian version of the PRTEE in tennis players.²⁰ In order to use this questionnaire for a Persian-speaking population, a rigorous process of cultural adaptation and evaluation of psychometric properties was needed.

The aims of this study were to: (i) cross-culturally adapt the PRTEE into Persian language and culture; and (ii) test its measurement properties (reliability and construct validity).

Methods

This study consisted of two phases: firstly, the PRTEE was translated into and cross-culturally adapted for the Persian language. In the second phase, reliability and construct validity were assessed. The medical ethical committee of the University of Social Welfare and Rehabilitation (USWR) approved the study protocol (IR.USWR.REC.1398.141).

Phase1: Translation and cross-cultural adaptation process

The process of translation was performed in five stages based on the guidelines developed by Beaton et al.²¹:

Initial translation: Two bilingual health professionals (a hand therapist and a hand surgeon) whose first language is Persian performed the initial translations separately. None of them were aware of the questionnaire concepts.

Synthesis of the translations: Two translators and one observer (ES) synthesized the results of the translations through consensus.

Back translation: Two translators who were blind to the original questionnaire did the back translation to identify ambiguous wording in the translations.

Expert committee review: To achieve cross-cultural equivalence, an expert committee consolidated all the versions of the questionnaire and developed the pre-final version. The committee comprised a methodologist, hand surgeon, hand therapist, and language professionals. Once the semantic and idiomatic equivalence was achieved, the final back-translated English version was sent to the developer of the PRTEE (JM) to check the items conceptually for potential areas of discrepancy.

Test of the pre-final version: In order to determine cognitive equivalence and debriefing, cognitive interviews with patients were used on the final version of the Persian PRTEE (P-PRTEE) questionnaire. Patients with a confirmed diagnosis of TE were interviewed for pilot testing to investigate their understanding of each individual item.²² Interviews continued until saturation was reached. Each participant was asked whether they had any difficulty to understand the sentences. Participants were also asked what they thought each question means. The meaning of the items, tasks, and the selected responses were also discussed.

Phase 2: Psychometric testing

Test–retest reliability, internal consistency, and measurement error were used to assess reliability.²³ Construct validity was assessed by hypothesis testing, where the strength of the relationship between the P-PRTEE and the DASH questionnaire was investigated.²⁴ The DASH questionnaire was used for convergent validity, because it measures the same construct as the PRTEE questionnaire. The visual analogue scale (VAS) was also used to evaluate the construct validity of the PRTEE pain subscale.

The DASH is a 30-item self-report questionnaire that measures physical function and symptoms in patients with musculoskeletal disorders. Each item is rated from 1 to 5, which means less difficulty or unable to do the activities, respectively. The total score is from 0 to 100, with 0 reflecting no difficulty and 100 severe disability. In this study we used the Persian version of DASH questionnaire.²⁵ The VAS is a measurement instrument used to quantify the pain intensity level of patients. Patients are asked to rate their pain on a 0 to 10 VAS, with higher scores indicating more pain intensity.²⁶

Participants

Between January 2018 and May 2019, 90 consecutive patients with TE were included. Clinical diagnosis of TE was confirmed by imaging results (simple radiography to rule out other pathologies), positive provocative tests, and a pain score of ≥3 cm on the VAS. Patients under 18 years old, with concomitant pathology in the wrist or shoulder, numbness in the dorsal radial part of hand, and inability to complete the questionnaire were excluded. Written informed consent was obtained from all of the participants at baseline. Demographic data were collected at baseline. Participants were asked to complete the Persian version of both the PRTEE and DASH questionnaires and to rate their pain based on the VAS on a single occasion. Participants were also asked to fill out the P-PRTEE questionnaire 48 h after initial data gathering.

Data analysis

Descriptive statistics were used to summarize participant characteristics.

To estimate the test–retest reliability, the intraclass correlation coefficient (ICC) was used. An ICC greater than 0.75 was considered as excellent reliability.²⁷ Internal consistency was assessed by means of Cronbach’s alpha. Values greater than 0.70 were considered as acceptable reliability.²⁸

To measure internal consistency and item discrimination index, item total correlation was used. Values of 0.4 and above were considered as very good internal consistency.²⁹

Standard error of measurement (SEM) is a measure of within-subject variability defined as the standard deviation at the baseline measure adjusted for the internal consistency (SEM = SD×√ 1 − r), which was used to measure the error of measurement.³⁰

Based on the SEM, the minimum detectable change (MDC; MDC₉₅ = SEM × 1.96× √2) was determined, which describes the amount of true change in patient status beyond measurement error with 95% certainty.

To investigate the construct validity, the relationship between the P-PRTEE and the DASH and between the pain subscale of the P-PRTEE and VAS were evaluated with the use of the Pearson correlation coefficient (r). An r value greater than 0.70 was considered a strong correlation.³¹

The level of statistical significance was set at p < 0.05. All analyses were conducted using SPSS version 23.

Results

Phase 1: Translation and cross-cultural adaptation

Most terms in the PRTEE were simple, easy to translate and understand. However, to culturally adapt, some items were modified. Items number 6 and 8 were modified in order to improve the practical equivalence and understanding of the translated questions. The modifications were done to improve understanding of the aimed activity due to cultural differences.

The phrase “doorknob” was omitted as it is not commonly used in the Persian population. This item was changed to “using a key to open a closed door”, after discussion with the developer to retain the concept of a common functional task requiring forearm rotation. Also, due to uncommon use of “coffee”, it was changed to “tea” in the item “lift a full coffee cup or glass of milk to your mouth’’.

The final version of the P-PRTEE was approved by the developer to be used for cognitive interviews. Cognitive interviews were conducted with five participants (3 female and 2 male, mean age of 40 years, ranged from 32 to 57) with TE. From the cognitive interviews, patients revealed that the P-PRTEE is easy to complete and they understood the items appropriately when asked.

Phase 2: Psychometric testing

A total of 90 consecutive patients with TE were enrolled from January 2018 to May 2019. The mean age was 46 years (standard deviation (SD = 11); ranged from 22 to 68). Symptom duration less than one month was seen in 18 (20%) patients and the remainder had symptoms more than one month. Sixty-two percent of patients were female, and 93% of patients were right handed (Table 1).

Table 1.

Demographic data of participants.

Variables	N (%) ormean (SD)
Sex
Female	56 (62%)
Male	34 (38%)
Mean age
years	46.4 (10.7)
Injured hand
Right	84 (93%)
Left	6 (7%)
Duration
<1 Month	18 (20%)
1–6 Months	56 (62%)
6–12 Months	6 (7%)
>1 year	10 (11%)
PRTEE total score—baseline
53.7 (±21.2)	53.7 (±21.2)

SD: standard deviation.

The ICC was 0.98 (95%CI = 0.97 to 0.99), indicating excellent test–retest reliability. Cronbach’s alpha of 0.94 and item total correlation of 0.55 (ranged from 0.55 to 0.76) indicated excellent internal consistency of the P-PRTEE. The lowest correlation (r = 0.55) belonged to two items of the pain subscale and total score of the P-PRTEE (pain at rest and when your pain was at its worst). The highest correlation (r = 0.76) was between the item “turn a key using my affected hand” and the total score of the P-PRTEE questionnaire (Table 2). The SEM was calculated based on the formula and was 5.4. Minimal detectable change, calculated based on the SEM value was 14.24.

Table 2.

Mean and SD of the items and item total correlation for the PRTEE.

Item	Mean (SD)	Item total correlation	Cronbach's alpha if item deleted
When you are at rest	4.2 (3.1)	0.55	0.94
When doing a task with repeated arm movement	6.3 (2.4)	0.68	0.93
When carrying a plastic bag of groceries	6.5 (2.7)	0.59	0.93
When your pain was at its least	2.7 (2.6)	0.72	0.94
When your pain was at its worst	7.9 (2.4)	0.55	0.94
Turn a key using my affected hand	3.5 (3.1)	0.76	0.94
Carry a grocery bag or briefcase by the handle	6.4 (2.6)	0.60	0.93
Lift a full coffee cup or glass of milk to your mouth	3.4 (2.9)	0.68	0.94
Open a jar	6.5 (3.2)	0.59	0.93
Pull up pants	3.9 (3.1)	0.71	0.93
Wring out a washcloth or wet towel	6.2 (3.2)	0.69	0.94
Personal activities (dressing, washing)	4.2 (2.7)	0.64	0.93
Household work (cleaning, maintenance)	5.8 (3.0)	0.57	0.94
Work (your job or everyday work)	6.04 (3.0)	0.68	0.94
Recreational or sporting activities	6.07 (2.9)	0.72	0.94

A strong, significant correlation was found between the total score of the P-PRTEE and the DASH questionnaire, indicating good construct validity of the P-PRTEE (r values = 0.85, p < 0.05). A strong correlation was found between the function subscale of the P-PRTEE and the DASH (r = 0.91, p < 0.05). A strong correlation was found between the pain subscale of the P-PRTEE and the DASH questionnaire (r = 0.74, p < 0.05). Pain, measured by the VAS, had a strong correlation with pain subscale of the P-PRTEE (r = 0.77, p < 0.05).

Discussion

The Persian version of the Patient-Rated Tennis Elbow Evaluation (P-PRTEE) questionnaire was cross-culturally adapted and shows excellent psychometric properties in terms of reliability (internal consistency and test–retest) and construct validity.

We followed the guidelines of the cross-cultural adaptation developed by Beaton et al. for translation.²¹ In the process of the cross-cultural adaptation of the P-PRTEE, we changed the term “doorknob” to “turn a key”, and the term “coffee” to “tea”, to be more reflective of the Persian culture. Except for these two terms in items number 6 and 8, no difficulties were found in the translated version of the questionnaire.

The P-PRTEE showed excellent test–retest reliability (ICC = 0.98). This result was expected, as it was similar to other studies.^{11,12,14,16,20} However, it was higher than the original version of the PRTEE³² (ICC = 0.89) and the French version¹⁵ (ICC = 0.86). This difference in the ICC value could be due to the difference of time interval for the test–retest evaluation in the French version (30 min), and the original version (one week later) in comparison to our study (48 h). We decided the 48-h time interval, because it seems long enough for patients to reduce the likelihood of remembering and repeating their responses while their conditions would not be changed.

The high Cronbach’s alpha of the Persian version of PRTEE (0.94) is similar to that of the Italian¹¹ (0.95), German³³ (0.94), Swedish¹³ (0.94), and Greek version¹⁸ (0.95). High values of Cronbach’s alpha (greater than 0.90) can indicate redundancy of the items, and further studies are needed to assess the effect of deleting some items in future development.²⁸

Two items of the pain subscale showed low correlation with total score of the PRTEE suggesting that these questions are not appropriate to measure pain in this context (pain at rest and how often do you have pain). Further factor analysis and Rasch analysis need to be undertaken to assess this. The strongest correlation was found between the item “turn a key using my affected hand” and total score of the PRTEE (r = 0.76). This strong correlation was expected, as the lateral epicondyle is the origin of the common supinator muscles that is involved in extension and supination of the wrist.

The small value of SEM (5.4) indicates that the P-PRTEE can evaluate changes precisely. The finding of MDC value (MDC₉₅ = 14.24) will help clinicians to determine relatively true changes following their interventions or over time.

In terms of construct validity, the total score of the P-PRTEE showed a high correlation with the total score of the DASH questionnaire (r = 0.85), which indicates excellent construct validity of the P-PRTEE. Previous studies reported moderate to strong correlations with the DASH ranging between 0.65^12,34 to 0.88.^11,13 This variation in the reported construct validity could be due to the different approaches in measurement of disability between the PRTEE and the DASH. In other words, what is measured by the DASH is the ability to perform activities in general, whilst the PRTEE measures the ability of patients to perform activities using their affected hand.

As there is no gold standard for the evaluation of pain and disability in the patients with TE, the VAS and the DASH questionnaires were used to evaluate the construct validity of the P-PRTEE. The DASH is believed to be the best instrument in the assessment of disability in patients with hand and upper limb injuries. The Persian version of the DASH is known to be reliable and valid in the hand injuries.²⁵ Therefore, the DASH was used for the construct validity evaluation. The pain and function subscales of the P-PRTEE had a strong correlation with the DASH questionnaire (r = 0.91 and 0.74, respectively). Furthermore, the VAS and the pain subscale of the P-PRTEE had a strong correlation (r = 0.77). These findings support the construct validity of the P-PRTEE.

There are some limitations to this study. Firstly, the sample size was too small to perform factor analysis for better determination of construct validity. Secondly, it might have been better to enroll patients before and after treatments to evaluate responsiveness of this questionnaire. Findings of item total correlation and MDC are the strengths of this study which can be used in future research.

Conclusions

The P-PRTEE as a disease-specific patient-reported measure captures different aspects of pain and function in patients with TE. The results of our study indicate excellent psychometric properties of the P-PRTEE and endorse the use of this questionnaire in clinical settings. This questionnaire can be used to evaluate pain and function, and also detect changes through time in the Persian population with TE.

Footnotes

Acknowledgement

The authors would like to thank Prof. Macdermid for her support in this paper.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Informed consent

Written informed consent was obtained from the patients for their anonymized information to be published in this article.

Ethical approval

Ethical approval for this study was obtained from ethics committee of the University of Social Welfare and Rehabilitation Sciences (IR.USWR.rec.1394.71).

Guarantor

MF.

Contributorship

MF and ES researched literature and conceived the study. AB and AV were involved in protocol development, gaining ethical approval, patient recruitment, and data analysis. AF was the surgeon in this study to confirm the diagnosis of TE. JM was supervisor of this study and controlled all the process of this study. MF and ES wrote the first draft of the manuscript. All authors reviewed and edited the manuscript and approved the final version of the manuscript.

ORCID iDs

Erfan Shafiee

Maryam Farzad

Joy Macdermid

Amirreza Smaeel Beygi

References

Dines

Bedi

Williams

, et al. Tennis injuries: epidemiology, pathophysiology, and treatment. J Am Acad Orthop Surg 2015; 23: 181–189.

Viola

A critical review of the current conservative therapies for tennis elbow (lateral epicondylitis). Australas Chiropr Osteopathy 1998; 7: 53.

Alizadehkhaiyat

Fisher

Kemp

, et al. Pain, functional disability, and psychologic status in tennis elbow. Clin J Pain 2007; 23: 482–489.

Hudak

Amadio

Bombardier

Development of an upper extremity outcome measure: the DASH (disabilities of the arm, shoulder, and head). Am J Ind Med 1996; 29: 602–608.

Janssen

De Smet

Responsiveness of the DASH questionnaire for surgically treated tennis elbow. Acta Chir Belg 2008; 108: 583–585.

MacDermid

JC.

Outcome evaluation in patients with elbow pathology: issues in instrument development and evaluation. J Hand Ther 2001; 14: 105–114.

Michener

McClure

Sennett

BJ.

American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, patient self-report section: reliability, validity, and responsiveness. J Shoulder Elbow Surg 2002; 11: 587–594.

Dowrick

Gabbe

Williamson

, et al. Outcome instruments for the assessment of the upper extremity following trauma: a review. Injury 2005; 36: 468–476.

Vincent

MacDermid

JC.

The Patient-Rated Elbow Evaluation (PREE). J Physiother 2012; 58: 274.

10.

MacDermid

Update: the patient-rated forearm evaluation questionnaire is now the patient-rated tennis elbow evaluation. J Hand Ther 2005; 18: 407–410.

11.

Cacchio

Necozione

MacDermid

, et al. Cross-cultural adaptation and measurement properties of the Italian version of the Patient-Rated Tennis Elbow Evaluation (PRTEE) questionnaire. Phys Ther 2012; 92: 1036–1045.

12.

Altan

Ercan

Konur

Reliability and validity of Turkish version of the patient rated tennis elbow evaluation. Rheumatol Int 2010; 30: 1049–1054.

13.

Nilsson

Baigi

Marklund

, et al. Cross-cultural adaptation and determination of the reliability and validity of PRTEE-S (Patientskattad Utvärdering av Tennisarmbåge), a questionnaire for patients with lateral epicondylalgia, in a Swedish population. BMC Musculoskelet Disord 2008; 9: 79.

14.

Van Ark

Zwerver

Diercks

, et al. Cross-cultural adaptation and reliability and validity of the Dutch Patient-Rated Tennis Elbow Evaluation (PRTEE-D). BMC Musculoskelet Disord 2014; 15: 270.

15.

Blanchette

Normand

MC.

Cross-cultural adaptation of the patient-rated tennis elbow evaluation to Canadian French. J Hand Ther 2010; 23: 290–299.

16.

Lee

D-R

Kim

J-S.

Reliability and validity of the Korean Version of Patient-Rated Tennis Elbow Evaluation. J Korean Soc Phys Med 2014; 9: 25–33.

17.

Kaux

Delvaux

Schaus

, et al. Cross-cultural adaptation and validation of the Patient-Rated Tennis Elbow Evaluation Questionnaire on lateral elbow tendinopathy for French-speaking patients. J Hand Ther 2016; 29: 496–504.

18.

Stasinopoulos

Papadopoulos

Antoniadou

, et al. Greek adaptation and validation of the Patient-Rated Tennis Elbow Evaluation (PRTEE). J Hand Ther 2015; 28: 286–290.

19.

Chung

Wiley

JP.

Validity, responsiveness and reliability of the Patient-Rated Tennis Elbow Evaluation. Hand Ther 2010; 15: 62–68.

20.

Mansoori

Noorizadeh Dehkordi

Mansour Sohani

, et al. Cross-cultural adaptation and determination of the validity and reliability of the Persian Version of the Patient-Rated Tennis Elbow Evaluation (PRTEE) questionnaire in Iranian tennis players. Func Disabil J 2019; 2: 17–26.

21.

Beaton

Bombardier

Guillemin

, et al. Guidelines for the process of cross-cultural adaptation of self-report measures. Spine (Phila 1976) 2000; 25: 3186–3191.

22.

Willis

GB.

Research synthesis: the practice of cross-cultural cognitive interviewing. Public Opin Q 2015; 79: 359–395.

23.

Cho

Kim

Cronbach’s coefficient alpha: well known but poorly understood. Organ Res Methods 2015; 18: 207–230.

24.

Brahma

Assessment of construct validity in management research: a structured guideline. J Manag Res 2009; 9: 59–71.

25.

Mousavi

Parnianpour

Abedi

, et al. Cultural adaptation and validation of the persian version of the Disabilities of the Arm, Shoulder and Hand (DASH) outcome measure. Clin Rehabil 2008; 22: 749–757.

26.

Nahler

Visual analogue scale (VAS). Dictionary of Pharmaceutical Medicine, Springer Verlag, Vienna, 2009, pp.189.

27.

Shrout

Fleiss

JL.

Intraclass correlations: uses in assessing rater reliability. Psychol Bull 1979; 86: 420–428.

28.

Tavakol

Dennick

Making sense of Cronbach’s alpha. Int J Med Educ 2011; 2: 53–55.

29.

Hwang

IH.

The usability of item-total correlation as the index of item discrimination. Korean J Med Educ 2000; 12: 45–51.

30.

Cerin

Standard error of measurement. In: Encyclopedia of quality of life and well-being research. Dordrecht: Springer, 2014.

31.

Hemphill

JF.

Interpreting the magnitudes of correlation coefficients. Am Psychol 2003; 58: 78–79.

32.

Rompe

Overend

MacDermid

JC.

Validation of the Patient-rated Tennis Elbow Evaluation Questionnaire. J Hand Ther 2007; 20: 3–10.

33.

John

Angst

Pap

, et al. Cross-cultural adaptation, reliability and validity of the patient rated elbow evaluation (PREE) for German-speaking patients. Clin Exp Rheumatol 2007; 25: 195–205.

34.

Vincent

MacDermid

JC.

Patient-rated tennis elbow evaluation questionnaire. J Physiother 2014; 60: 240.